Ketamine and other drugs

KETAMINE AND OTHER DRUGS

Ketamine

  • Dissociative agent – causes profound analgesia, immobility, amnesia with light sleep, and feeling of dissociation from one’s own body and surroundings.
  • Primarily acts on the cortex. Inhibits glutamate receptor, analgesia partly through opioid receptors. May interfere with  glutamate and NMDA receptors. 
  • Can be given both intravenous and intamuscular
  • On anaesthesia some reflexes remain active – cough, pharyngeal etc. hence may not be suitable for surgeries for endosopy or oropharyngeal surgery
  • Good for brief operations and repeated use
  • Ketamine presented as 5 ml or 10 ml vials (100 mg / ml)
  • Stable for 3 years
  • Rapid induction (slower than thiopental)
  • No drug accumulation
  • Rapidly metabolized by liver (metabolite – norketamine – hypnotic - long standing drowsiness and prolonged recoveries in large doses)
  • Central stimulation of sympathetic system stimulation of CVS (tachycardia, high BP)
  • Large doses direct depression of myocardium
  • Produces good analgesia
  • Increased muscle tone. So muscle relaxant needed

Problems in Ketamine

  • Humans - dreams and hallucinogens
  • Cats – maybe thrown to convulsions if subjected to any noise and other disturbances
  • Corneal drying due to open eyes – bland ophthalmic ointment in eyes
  • Depth of anaesthesia – difficult to judge – inexperienced person may go for more and more amount of the drug
  • Combination with alpha-2 agonist – may lead to vomition in some cases
  • Popularly ketamine is used in combination with xylazine or xylazine- diazepam in many species for muscle relaxation.

Tiletamine

  • More potent, longer acting, greater side effects
  • Tiletamine + zolazepam—combination is found to be useful.
Last modified: Sunday, 27 November 2011, 10:22 AM